We have a bootstrapper that checks for and installs .NET and the French .NET language pack.
We're just updating it to install .NET 4.6.1. However, when installing the French language pack on Windows 10 we get an error message (in French) saying that the language pack is already installed:
Le module linguistique de .NET Framework 4.6.1 (Français) ne correspond à la langue du système d'exploitation Windows installé sur votre ordinateur. Modifiez vos paramètres linguistiques ou installez le module linguistique applicable au système d'exploitation installé avant d'installer ce package.
Language Interface Pack (LIP): A partially localized language pack that includes less than 100 percent of the localized resources. LIPs can be installed only on top of a fully localized language pack. For end users, what we can do is installing language interface pack, which is partially localized for some languages. This explains why you might install a Portuguese language pack, but still get some parts display in English after a reboot. See diagrams for details here.
Le module linguistique de .NET Framework 4.6.1 (Français) est déjà installé sur votre ordinateur. Pour l'activer, installez le module linguistique correspondant au système d'exploitation installé.
Google translate translates it to:
The language pack for the .NET Framework 4.6.1 (French) does not correspond to the Windows operating system language installed on your computer. Change your language settings or install the applicable language pack for the operating system installed before installing this package.
The language pack for the .NET Framework 4.6.1 (French) is already installed on your computer. To activate, install the language pack corresponding to the installed operating system.
We've tried the .NET 4.5.1 French language pack and it comes up with a similar error. It installs fine on Windows 7.
What's changed in Windows 10 that means we get this error message? It seems to be implying that the French language pack is already installed as part of Windows 10. If so, what is the point of having the Windows 10 language pack installers at all?